From left, Michelle Obama's mother Marian, Malia and Sasha Obama, their mother Michelle and Dr. Jill Biden, wife of Vice President Biden, listen to President Barack Obama at the Democratic National Convention in Charlotte, N.C., on Thursday, Sept. 6, 2012. (AP Photo/Lynne Sladky) less

From left, Michelle Obama's mother Marian, Malia and Sasha Obama, their mother Michelle and Dr. Jill Biden, wife of Vice President Biden, listen to President Barack Obama at the Democratic National Convention ... more

FILE - In this Wednesday, Sept. 5, 2012 file photo, President Barack Obama waves after former President Bill Clinton addressed the Democratic National Convention in Charlotte, N.C. President Obama caps the convention Thursday, Sept. 6, with a prime time acceptance speech aimed at forcefully making his case for re-election: The economy is still weak but getting better, and America is absolutely better off than when he took office in perilous times. (AP Photo/David Goldman, File) less

FILE - In this Wednesday, Sept. 5, 2012 file photo, President Barack Obama waves after former President Bill Clinton addressed the Democratic National Convention in Charlotte, N.C. President Obama caps the ... more

Democratic presidential candidate Sen. Barack Obama, D-Ill., makes a call to a voter, as he tosses an orange, during a stop at the Obama Kansas City campaign office in Kansas City, Mo. Saturday, Oct. 18, 2008.

Democratic presidential candidate Sen. Barack Obama, D-Ill., makes a call to a voter, as he tosses an orange, during a stop at the Obama Kansas City campaign office in Kansas City, Mo. Saturday, Oct. 18, 2008.

Democratic presidential hopeful, Sen. Barack Obama, D-Ill., right, and Rick Jones, 59, chat while eating breakfast at Four Seasons Family Restaurant in Greenwood, Ind., Tuesday, May 6, 2008, as voters in both Indiana and North Carolina crowd polling places Tuesday for the states' primary elections. . less

Democratic presidential hopeful, Sen. Barack Obama, D-Ill., right, and Rick Jones, 59, chat while eating breakfast at Four Seasons Family Restaurant in Greenwood, Ind., Tuesday, May 6, 2008, as voters in both ... more

Supporters of Democratic presidential candidate Sen. Barack Obama, D-Ill. line up and cheer him on in Dunn, N.C. on Sunday, Oct. 19, 2008. Obama later held a rally in Fayetteville. (AP Photo/The Fayetteville Observer,Stephanie Bruce) ** MAGS OUT, NO SALES ** less

Supporters of Democratic presidential candidate Sen. Barack Obama, D-Ill. line up and cheer him on in Dunn, N.C. on Sunday, Oct. 19, 2008. Obama later held a rally in Fayetteville. (AP Photo/The Fayetteville ... more

Democratic presidential hopeful Sen. Barack Obama, D-Ill., second from left, is greeted by a supporter during a rally for Obama in East Rutherford, N.J., Monday, Feb. 4, 2008, in the final campaign push before Super Tuesday. less

Democratic presidential hopeful Sen. Barack Obama, D-Ill., second from left, is greeted by a supporter during a rally for Obama in East Rutherford, N.J., Monday, Feb. 4, 2008, in the final campaign push before ... more

Democratic presidential candidate Sen. Barack Obama D-Ill. accepts an article from an audience member that their grandson wrote during, Friday, June 13, 2008, a speech at the Oakleaf Village retirement community in Columbus, Ohio. less

Democratic presidential candidate Sen. Barack Obama D-Ill. accepts an article from an audience member that their grandson wrote during, Friday, June 13, 2008, a speech at the Oakleaf Village retirement ... more

Democratic presidential hopeful, Sen. Barack Obama D-Ill., meets with workers at the Rite-Aid Distribution Center during a campaign stop in Waterford, Mich. Monday, June 2, 2008. Obama effectively clinched the Democratic presidential nomination Tuesday, June 3, 2008, based on an Associated Press tally of convention delegates, ahead of the results from the day's final primaries in Montana and South Dakota. less